Question

Medical staff are reassessing a $65$-year-old female patient in the critical care ward due to increasing somnolence and tachypnea. The patient was hospitalized $72$ hours prior for septic shock complicating severe community-acquired pneumonia. Initial management included aggressive intravenous fluid resuscitation and empiric antimicrobial therapy with intravenous vancomycin and piperacillin-tazobactam. She has a past medical history of chronic obstructive pulmonary disease and left ventricular hypertrophy. Yesterday, her hemodynamics improved, allowing the discontinuation of vasopressor support. Today, the blood cultures obtained on admission demonstrate heavy growth of Streptococcus pneumoniae, which is reported as susceptible to ceftriaxone and penicillin.

Currently, the patient appears lethargic and is using accessory muscles of respiration. Current vital signs include a temperature of $37.8^\circ C$ ($100.0^\circ F$), blood pressure of $115/75\ mmHg$, heart rate of $105/min$, and a respiratory rate of $30/min$. Pulse oximetry indicates an oxygen saturation of $90\%$ while receiving supplemental oxygen via a high-flow nasal cannula. Physical examination reveals diminished breath sounds bilaterally without jugular venous distention. A bedside point-of-care ultrasound demonstrates a collapsible inferior vena cava and a predominant A-line pattern bilaterally without significant B-lines.

Laboratory evaluation is notable for:
Sodium: $138\ mEq/L$
Chloride: $104\ mEq/L$
Bicarbonate: $15\ mEq/L$
Blood urea nitrogen: $32\ mg/dL$
Creatinine: $1.8\ mg/dL$

An arterial blood gas analysis reveals:
$pH$: $7.22$
$PaCO_2$: $38\ mmHg$
$PaO_2$: $62\ mmHg$
$HCO_3^-$: $15\ mEq/L$

Which of the following are appropriate next steps in the management of this patient? (Select all that apply)